From 7ce331c01ce6eb7b3f5c715a38a24359da9c6ee2 Mon Sep 17 00:00:00 2001
From: Eric Andersen <andersen@codepoet.org>
Date: Thu, 22 Nov 2001 14:04:29 +0000
Subject: Totally rework the math library, this time based on the MacOs X math
 library (which is itself based on the math lib from FreeBSD).  -Erik

---
 libm/double/arcdot.c | 110 ---------------------------------------------------
 1 file changed, 110 deletions(-)
 delete mode 100644 libm/double/arcdot.c

(limited to 'libm/double/arcdot.c')

diff --git a/libm/double/arcdot.c b/libm/double/arcdot.c
deleted file mode 100644
index 44c057229..000000000
--- a/libm/double/arcdot.c
+++ /dev/null
@@ -1,110 +0,0 @@
-/*							arcdot.c
- *
- *	Angle between two vectors
- *
- *
- *
- *
- * SYNOPSIS:
- *
- * double p[3], q[3], arcdot();
- *
- * y = arcdot( p, q );
- *
- *
- *
- * DESCRIPTION:
- *
- * For two vectors p, q, the angle A between them is given by
- *
- *      p.q / (|p| |q|)  = cos A  .
- *
- * where "." represents inner product, "|x|" the length of vector x.
- * If the angle is small, an expression in sin A is preferred.
- * Set r = q - p.  Then
- *
- *     p.q = p.p + p.r ,
- *
- *     |p|^2 = p.p ,
- *
- *     |q|^2 = p.p + 2 p.r + r.r ,
- *
- *                  p.p^2 + 2 p.p p.r + p.r^2
- *     cos^2 A  =  ----------------------------
- *                    p.p (p.p + 2 p.r + r.r)
- *
- *                  p.p + 2 p.r + p.r^2 / p.p
- *              =  --------------------------- ,
- *                     p.p + 2 p.r + r.r
- *
- *     sin^2 A  =  1 - cos^2 A
- *
- *                   r.r - p.r^2 / p.p
- *              =  --------------------
- *                  p.p + 2 p.r + r.r
- *
- *              =   (r.r - p.r^2 / p.p) / q.q  .
- *
- * ACCURACY:
- *
- *                      Relative error:
- * arithmetic   domain     # trials      peak         rms
- *    IEEE      -1, 1        10^6       1.7e-16     4.2e-17
- *
- */
-
-/*
-Cephes Math Library Release 2.3:  November, 1995
-Copyright 1995 by Stephen L. Moshier
-*/
-
-#include <math.h>
-#ifdef ANSIPROT
-extern double sqrt ( double );
-extern double acos ( double );
-extern double asin ( double );
-extern double atan ( double );
-#else
-double sqrt(), acos(), asin(), atan();
-#endif
-extern double PI;
-
-double arcdot(p,q)
-double p[], q[];
-{
-double pp, pr, qq, rr, rt, pt, qt, pq;
-int i;
-
-pq = 0.0;
-qq = 0.0;
-pp = 0.0;
-pr = 0.0;
-rr = 0.0;
-for (i=0; i<3; i++)
-  {
-    pt = p[i];
-    qt = q[i];
-    pq += pt * qt;
-    qq += qt * qt;
-    pp += pt * pt;
-    rt = qt - pt;
-    pr += pt * rt;
-    rr += rt * rt;
-  }
-if (rr == 0.0 || pp == 0.0 || qq == 0.0)
-  return 0.0;
-rt = (rr - (pr * pr) / pp) / qq;
-if (rt <= 0.75)
-  {
-    rt = sqrt(rt);
-    qt = asin(rt);
-    if (pq < 0.0)
-      qt = PI - qt;
-  }
-else
-  {
-    pt = pq / sqrt(pp*qq);
-    qt = acos(pt);
-  }
-return qt;
-}
-- 
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